One hundred pts with coronary artery disease (CAD) without diagnostic Q waves and with normal resting left ventricular ejection fraction (LVEF) were assessed by radionuclide angiography to determine regional and global LV function during exercise. LVEF with exercise was not different from rest in pts with one vessel disease (LV), but was significantly lower in pts with 2VD, 3VD, and left main disease. The prevalence of abnormal regional and global LV exercise responses increased in stepwise fashion from pts with one VD, 2VD, 3VD, through left main disease. Thus, the sensitivity of detecting CAD by radionuclide imaging is related to the anatomic extent of CAD and will therefore be determined by selection of the patient population.